Field of the Invention
The present invention relates to a fuel cell combustor for supplying a combustion gas to a fuel cell stack formed by stacking a plurality of fuel cells for generating electrical energy by electrochemical reactions of a fuel gas and an oxygen-containing gas. Further, the present invention relates to a fuel cell module including the combustor and the fuel cell stack.
Description of the Related Art
In general, a solid oxide fuel cell (SOFC) employs a solid electrolyte. The solid electrolyte is an oxide ion conductor such as stabilized zirconia. The solid electrolyte is interposed between an anode and a cathode to form an electrolyte electrode assembly (hereinafter also referred to as the MEA). The electrolyte electrode assembly is sandwiched between separators (bipolar plates). In use, generally, predetermined numbers of the electrolyte electrode assemblies and the separators are stacked together to form a fuel cell stack.
In the SOFC, since the operating temperature is relatively high, it is required to raise the temperature of the stacked fuel cells to the desired temperature beforehand. As a known technique of raising the temperature in such a situation, for example, Japanese Laid-Open Patent Publication No. 2011-113890 discloses an off gas combustion apparatus and an off gas combustion method for a solid oxide fuel cell.
This off gas combustion apparatus includes a mixture suppression region and a mixture promotion region. The mixture suppression region consists of partition plates each extending, so as not to mix at an early stage, a fuel electrode off gas and an air electrode off gas discharged from a tip of a fuel cell bundle. The mixture promotion region has a hole formed at an upper position of the partition plates to promote mixing of the fuel electrode off gas and the air electrode off gas at a latter stage.
According to the disclosure, it is possible to suppress mixing of the fuel electrode off gas and the air electrode off gas at the tip end of the solid oxide fuel cell bundle.
Therefore, according to the disclosure, by placing the position heated in combustion to be remote from the tip end of the fuel cell bundle to reduce the heat distribution difference in the fuel cell bundle, it becomes possible to prolong the service life of the fuel cell bundle.